Lathe-dog.



PA TENTED JAN. 28, 1908. G. J. BLUM. I LATHE DOG. APPLIOATION FILED JUNE13. 1904 GEORGE .I. BLUM, OF CHICAGO, ILLINOIS.

LATHE-DOG.

Specification of Letters Patent.

Patented Jan. 28, 1908.

Application filed June 13.1904. Serial No. 212.362.

To all whom it may concern:

Be it known that I, Gnonen J. BLUM, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Lathe-Dogs, of which thefollowing is a specification.

In lathe dogs as heretofore constructed, the jaws are moved relativelyto each other by means of tightening screws passing through suitableopenings in said aws near opposlte ends thereof, the openings in one ofsaid jaws being screw-threaded to receive said screws. In theconstruction just outlined, when a tapering shaft or similar object isheld between the jaws of the dog, and the screws tightly set, one orboth of said screws are likely to be bent by the tilting of the jaws toassume an angle corresponding with that of the surface of the objectheld between them. Also, if one screw is tightened more than the other,so that the parallel relation of the jaws is disturbed, said screws willbe bent. The bending of the tightening screws interferes with the freeaction of the dog by making the screws very diflicult to turn, andsuccessive bendings weakens them so that they finally will break.

The object of this invention is to overcome the objections hereinbeforementioned, by the production of a lathe dog, the tightening screws ofwhich have a universal movement with relation to the aws, thuspermitting said jaws to be inclined, either transversely or in thedirection of their length, without subjecting said screws to strainsother than in the direction of their length.

In the accompanying drawings, Figure 1 is a perspective view of a lathedog embodying the features of my invention, the dog being represented asclamping a tapered object. Fig. 2 is a vertical central section throughsaid lathe dog.

In the embodiment of this invention I provide a head jaw 1 having aholding face 2 and.

an integral strengthening web 3 rearwardly of said face. Near its endsthe head jaw is provided with openings 4 extending therethrough, theouter ends of said openings being in the form of outwardly openingsockets 5, while the inner ends of the openings are bell-mouth orfiaring, as at 6.

The tail jaw 7 corresponds substantially in general outline with thehead jaw 1, having a grasping face 8 and an integral strengthening web9, and is also provided with an integral tail or stem 10 of the usualform. Near its ends and coinciding with the openings 4 in the head jawsaid tail jaw is provided with openings 11 having flaring inner endportions 12 and rectangular outer pockets 13, the inner ends of whichrectangular pockets are of cup or socket form.

Holding screws 14 are adapted to extend through the openings 4 and 11 ofthe two holding jaws 1 and 7. The heads 15 of said screws are squared attheir upper ends to receive a wrench, while the lower portions 16 ofsaid heads are spherical or ball-shape to correspond with the sockets 5of the outer ends of the openings 4 in the head jaw 1. Nuts 17 arescrew-threaded to fit upon the screws 14, the upper ends of said nutsbeing hemispherical in form to correspond with the cupped inner ends ofthe pockets 13.

The adjacent or holding faces of the holding jaws 1 and 7 are notched,as at 18, in the usual manner, and in this instance are provided withfacings 19 of brass or other suitable metal, set into the faces of saidholding aws.

In operation, this improved lathe dog is placed upon the work in theusual manner, and when the screws 1 and 7 are tightened and the jawsbrought firmly in contact with the surface of the object between themsaid jaws are at liberty to move with relation to said screws, eithertilting longitudinally if one screw is tightened more than the other, oroscillating transversely if the object grasped is tapering or irregularin outline. The openings 4 and 11 through which the tightening screws 7extend are in their smallest diameters somewhat greater than thediameter of the screws, and the flaring inner ends of both openings 4and 11 permit said screws to have a considerable movement with relationto said jaws. This movement between the jaws and the screws is carriedat the upper ends of the screws upon the spherical portions 16 of saidscrews bearing in the sockets 5 in the outer portions of the openings 4,and between the nuts 17 and the tail jaw 7 by the ball-shape inner endof each of the nuts bearing in the cupped or socket end of therectangular pockets 13.

It is apparent that various changes may be made in the embodiment hereinshown of this invention without departing from the spirit and scope ofthe invention, wherefore screws having a rounded portion adapted to fitinto the corresponding socket of the other jaw, said lastmentioned'socket being outwardly flaring and deep enough to containsubstantially the entire nut and corresponding substantially inhorizontal cross-section with the form of said nut, whereby said nut isfree to oscillate in any direction in said socket but is held fromturning on its axis.

GEORGE J. BLUM. Witnesses:

L. L. MILLER, GEORGE L. OHINDAHL.

I desire to have it understood that I do not j limit myself to theparticular construction herein illustrated and described.

I claim as my invention:

5 In a lathe dog, in combination, two holding jaws, each of said jawshaving an opening extending therethrough at each of its ends, the outerend of each of said openings being of socket form and the inner endthereof 10 flaring; screws connecting the corresponding 1 ends of saidjaws, the head of each of said screws being rounded to correspond withone of said sockets; and a nut on each of said

